Abstract: The dynamic recrystallization behavior of Al-Mn-Mg alloy for fusing roller during hot deformation process was investigated by using Gleeble-1500 thermal simulation test machine.The microstructure of the alloy under different compression conditions was analyzed using optical microscopy and transmission electron microscopy.The results show that after deformation the mean dynamic recovery subgrain size increased with the decrease of Z,the reciprocal of the subgrain size had a good linear relationship with the natural logarithm of both Z value and hyperbolic term of flow stress.The main softening mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization with decreasing the Z value.The dynamic recrystallization only occurred at low Z values,which must be below or equal to a constant of 1.93×1013 s-1.